Extended item_db.conf to have several other formats.

item_db.conf now supports:
BuyingStore(item_buyingstore.txt),Delay(item_delay.txt),Trade(item_trade.txt),Nouse(item_nouse.txt),Stack(item_stack.txt),Sprite(item_avail.txt)

Additional Information: http://hercules.ws/board/topic/5604-extending-item-dbconf/?view=getnewpost